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| $PostgreSQL: pgsql/doc/src/sgml/ref/release_savepoint.sgml,v 1.6 2006/09/16 00:30:19 momjian Exp $ |
| PostgreSQL documentation |
| --> |
| |
| <refentry id="SQL-RELEASE-SAVEPOINT"> |
| <refmeta> |
| <refentrytitle id="SQL-RELEASE-SAVEPOINT-TITLE">RELEASE SAVEPOINT</refentrytitle> |
| <refmiscinfo>SQL - Language Statements</refmiscinfo> |
| </refmeta> |
| |
| <refnamediv> |
| <refname>RELEASE SAVEPOINT</refname> |
| <refpurpose>destroy a previously defined savepoint</refpurpose> |
| </refnamediv> |
| |
| <indexterm zone="sql-release-savepoint"> |
| <primary>RELEASE SAVEPOINT</primary> |
| </indexterm> |
| |
| <indexterm zone="sql-release-savepoint"> |
| <primary>savepoints</primary> |
| <secondary>releasing</secondary> |
| </indexterm> |
| |
| <refsynopsisdiv> |
| <synopsis> |
| RELEASE [ SAVEPOINT ] <replaceable>savepoint_name</replaceable> |
| </synopsis> |
| </refsynopsisdiv> |
| |
| <refsect1> |
| <title>Description</title> |
| |
| <para> |
| <command>RELEASE SAVEPOINT</command> destroys a savepoint previously defined |
| in the current transaction. |
| </para> |
| |
| <para> |
| Destroying a savepoint makes it unavailable as a rollback point, |
| but it has no other user visible behavior. It does not undo the |
| effects of commands executed after the savepoint was established. |
| (To do that, see <xref linkend="sql-rollback-to" |
| endterm="sql-rollback-to-title">.) Destroying a savepoint when |
| it is no longer needed may allow the system to reclaim some resources |
| earlier than transaction end. |
| </para> |
| |
| <para> |
| <command>RELEASE SAVEPOINT</command> also destroys all savepoints that were |
| established after the named savepoint was established. |
| </para> |
| </refsect1> |
| |
| <refsect1> |
| <title>Parameters</title> |
| |
| <variablelist> |
| <varlistentry> |
| <term><replaceable>savepoint_name</replaceable></term> |
| <listitem> |
| <para> |
| The name of the savepoint to destroy. |
| </para> |
| </listitem> |
| </varlistentry> |
| </variablelist> |
| </refsect1> |
| |
| <refsect1> |
| <title>Notes</title> |
| |
| <para> |
| Specifying a savepoint name that was not previously defined is an error. |
| </para> |
| |
| <para> |
| It is not possible to release a savepoint when the transaction is in |
| an aborted state. |
| </para> |
| |
| <para> |
| If multiple savepoints have the same name, only the one that was most |
| recently defined is released. |
| </para> |
| |
| </refsect1> |
| |
| <refsect1> |
| <title>Examples</title> |
| |
| <para> |
| To establish and later destroy a savepoint: |
| <programlisting> |
| BEGIN; |
| INSERT INTO table1 VALUES (3); |
| SAVEPOINT my_savepoint; |
| INSERT INTO table1 VALUES (4); |
| RELEASE SAVEPOINT my_savepoint; |
| COMMIT; |
| </programlisting> |
| The above transaction will insert both 3 and 4. |
| </para> |
| </refsect1> |
| |
| <refsect1> |
| <title>Compatibility</title> |
| |
| <para> |
| This command conforms to the <acronym>SQL</> standard. The standard |
| specifies that the key word <literal>SAVEPOINT</literal> is |
| mandatory, but <productname>PostgreSQL</productname> allows it to |
| be omitted. |
| </para> |
| </refsect1> |
| |
| <refsect1> |
| <title>See Also</title> |
| |
| <simplelist type="inline"> |
| <member><xref linkend="sql-begin" endterm="sql-begin-title"></member> |
| <member><xref linkend="sql-commit" endterm="sql-commit-title"></member> |
| <member><xref linkend="sql-rollback" endterm="sql-rollback-title"></member> |
| <member><xref linkend="sql-rollback-to" endterm="sql-rollback-to-title"></member> |
| <member><xref linkend="sql-savepoint" endterm="sql-savepoint-title"></member> |
| </simplelist> |
| </refsect1> |
| </refentry> |